MS can do it because they control their own file formats. They have months/years to implement their own file formats before they announce them and release the software that uses them.
They do not provide other software authors the file specifications, so companies like SoftMaker have to reverse engineer the file formats if they want their software to read and write Microsoft formats. This process takes a lot of time and is subject to error.
Even if Microsoft released accurate file format information at the time they released new versions of their software, other companies would be months/years behind Microsoft in implementing those new file formats.